" If “piracy” means using value from someone else’s creative property without permission from that creator–as it is increasingly described today – then every industry affected by copyright today is the product and beneficiary of a certain kind of piracy. Film, records, radio, cable TV… Extremists in this debate love to say “You wouldn’t go into Barnes & Noble and take a book off of the shelf without paying; why should it be any different with online music?” The difference is, of course, that when you take a book from Barnes & Noble, it has one less book to sell. By contrast, when you take an MP3 from a computer network, there is not one less CD that can be sold. The physics of piracy of the intangible are different from the physics of piracy of the tangible. "

― Lawrence Lessig , Free Culture: The Nature and Future of Creativity